R.F. O'Sullivan & Son

Ordering a Sully’s cheeseburger presents a delectable choice: Will it be cheddar, Swiss, or smoked Gouda? Boursin or bleu? These are just a few of the more than two dozen topping combinations offered at the Somerville pub, where the grill masters turn patties as thick as meatballs into half-pound treats as juicy as a fine cut of Châteaubriand.